System and method for detection of an accessory device connection status

ABSTRACT

Embodiments of this invention provide for a portable computer that determines whether an accessory device is actively connected to it. In one embodiment, the portable computer may include a signal line accessible through an output of the portable computing device. The signal line may be connected to a communication device such as a communication cradle. The portable computer may detect a signal on the signal line to determine whether the communication device is actively connected to the portable computer. If the communication device is actively connected, the portable computer suspends implementation of a time-out feature that would otherwise reduce power consumption of the portable computer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to a portable computing device. Morespecifically, embodiments of this invention provide for detecting and/ordetermining a type of an accessory device connected to a portablecomputing device.

2. Description of the Related Art

Portable computers such as laptop and handheld computers may be providedwith additional capabilities through the use of accessory devices. Theaccessory devices may electrically couple to a processor of the portablecomputer to provide communication capabilities and external power.Accessory devices in general have been used to add functions andresources to portable computers to compensate for inherent limitationsarising from their size and mobility. Previous accessory devices havebeen used to provide, among other things, an alternating current (A/C)supply, serial and parallel ports, modems, additional memory, anduniversal serial ports. The portable computer may use accessory devicesto communicate with larger computers and data networks.

Portable computers are typically equipped with a time-out feature thatturns the computer off after a predetermined duration of inactivity. Thetime-out feature is designed to preserve battery life. While thetime-out feature may be necessary when the portable computer isoperating from an internal battery source, accessory devices may supplyan A/C converter to the portable computer to eliminate the need for thetime-out feature. However, previous portable computers provide for thetime-out feature to be enabled so that the portable computer switchesoff after a period of inactivity, even if the accessory device issupplying external power. Still, other portable computers, such asZaurus™ personal digital assistant manufactured by the Sharp Corp. andPalmPilot™ organizers manufactured by the 3Com Corp., disable thetime-out feature only when an A/C power adapter is supplied to a powerterminal of the portable computer.

These devices do not disable the time-out feature when an accessorydevice such as a communication cradle is connected to the portablecomputer through a communications port. In such instances, the time-outfeature can be limiting and a nuisance to the user by precluding, forexample, use of programs that require minimal user interaction.Therefore, there is a need for enabling the portable computer to detectwhether an accessory device supplying external power is activelyconnected to the portable computer.

Furthermore, a number of different types of accessories are availablefor use with portable computers. However, previous portable computersare not equipped to automatically determine the type of accessory devicethat is actively connected to the portable computer. Without thisability, the user is required to perform additional software functionsto identify the particular accessory device for the portable computer.In addition, the portable computer may accidentally execute anapplication for an accessory device other than the one being used. Incertain applications, this can be harmful to the portable computerand/or the accessory device. For example, the Palmpilot III™ may accessa modem accessory device by executing a software application configuredonly for modem devices. In some instances, the software application maybe damaging if the accessory device connected to the portable computeris erroneously identified as a modem device. Therefore, there is a needfor enabling the portable computer to automatically determine the typeof the accessory actively connected to it.

These and other shortcomings of previous portable computers will beaddressed by various embodiments of this invention.

SUMMARY OF THE INVENTION

Embodiments of this invention provide for a portable computer thatdetermines whether an accessory device is actively connected to it. Inone embodiment, the portable computer may include a signal lineaccessible through an output of the portable computing device. Thesignal line may be connected to a communication device such as acommunication cradle. The portable computer may detect a signal on thesignal line to determine whether the communication device is activelyconnected to the portable computer. If the communication device isactively connected, the portable computer suspends implementation of atime-out feature that would otherwise reduce power consumption of theportable computer.

Embodiments of this invention eliminate time constraints present inprevious devices that require the user to periodically interact with theportable computer in order to sustain its operation. As a result, theportable computer may operate programs continuously by connecting to anaccessory device such as a communications cradle through acommunications or output port. In this way, when the portable computeris connected to the communication device, the portable computer maycontinuously display, for example, a clock, photographs, or calendars.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a portable computing device that may incorporate anembodiment of the invention.

FIG. 2 is a schematic of an embodiment of this invention for detectingan accessory device actively connected to a portable computing device.

FIG. 3 is an embodiment of this invention for detecting a type of anaccessory device connected to the portable computing device.

FIG. 4A is another embodiment of this invention for detecting a type ofan accessory device connected to the portable computing device.

FIG. 4B is another embodiment of this invention for detecting a type ofan accessory device connected to the portable computing device.

FIG. 5 is a flowchart of an algorithm for detecting a communicationdevice actively connected to the portable computing device.

FIG. 6 is a flowchart of another algorithm for determining a type of anaccessory connected to the portable computing device.

DETAILED DESCRIPTION

An embodiment of this invention provides for detecting a type ofaccessory device connected to a portable computer. The portable computerthen implements software to accommodate the specific accessory devicedetected. Another embodiment of this invention provides for detectingwhether a communication accessory, such as a communication cradle, isactively connected to the portable computer. The portable computer thensuspends a time-out feature, as the communication device suppliesexternal power to the portable computer.

This disclosure initially describes a portable computer and accessorydevice for use with various embodiments of the invention, including userfeatures of the portable computer that may be affected or altered. InFIG. 2 and accompanying text, the disclosure describes hardware fordetecting whether an accessory device is connected to the portablecomputer. In FIGS. 3, 4A, and 4B and text accompanying these figures,the disclosure describes embodiments for detecting the type of accessorydevice connected to the portable computer. In FIG. 5 and accompanyingtext, an algorithm is presented for detecting whether the accessorydevice is actively connected to the portable computer. In FIG. 6 andaccompanying text, an algorithm is described for detecting an accessorytype connected to the portable computer,.

In an embodiment of this invention, the portable computer includes threemodes of operation. For purpose of this disclosure, an “on-mode” is amode in which a processor of the portable computer is fully operational.A “doze-mode” is a mode in which a processor is operating fewerfunctions to conserve energy. For example, in the doze-mode, a displaymay be on, but a user may experience a pause between the time an inputin entered and processed. In the “sleep-mode”, the portable computer isin its lowest state of power consumption, where the display is off and aprocessor is performing minimal functions such as time-keeping.

For purposes of this description, a computer is a combination of aprocessor and a memory. A portable computer is a computer having aportable energy resource. Handheld computers are portable computersdesigned to be held with one hand.

Portable Computer and Accessory Device

With reference to FIG. 1 an embodiment of this invention includes aportable computer 100 and an accessory device. Preferably, the portablecomputer 100 has interactive hardware and software that performfunctions such as maintaining calendars and phone lists. The portablecomputer 100 shown in FIG. 1 includes a plurality of input functionskeys 115 and a display 114 having graphic user interface features. Thedisplay 114 may be provided with an interface that allows the user toselect and alter displayed content using a pointer such as a stylus. Inan embodiment, the display 114 also includes a Graffiti™ writing section118 for tracing alphanumeric characters as input. A plurality ofapplication buttons 117 for performing automated or pre-programmedfunctions may be provided on a portion of the display 114. The portablecomputer 100 may also include an antenna for receiving wirelesscommunications. An example of a suitable portable computer 100 for usewith embodiments of this invention include handheld computers such asPalmPilot™, Palm III™, Palm IV™, Palm V™ organizers, manufactured by the3Com Corporation. Other embodiments of the invention can include WindowsCE™ portable computers, or other handheld computers and personal digitalassistants.

The stylus for inputting information onto the display 114 may slideablymount to a rail (not shown) on one of the lateral sides 122 of theportable computer 100. In an embodiment, the rail may be provided withlogic and electromechanical switches to perform functions based on themovement and position of the stylus. The rail may provide an “on/off”function, where removal of the stylus activates the portable computer100 for user operation. For example, removal of the stylus may actuate aswitch (not shown) implemented with the rail to activate the portablecomputer 100. The switch may be formed from an electromagnetic couplingbetween a metal stylus and a conductive element on the rail, whereremoval of the stylus forces a current. In another embodiment, a springhaving a conductive surface may biasly obstruct the path of the stylusalong the rail, so that removal of the stylus alters the length of thespring to close the switch.

As will be further described, the accessory device may include a plug-incommunication cradle 150 having a parallel port for data transfer with adata network or another computer. Other embodiments may provide foranother type of accessory device that equips the portable computer 100with, for example, serial communication abilities as provided by a modemdevice or Universal Serial Bus (USB) cradle. The communication cradle150 includes a stand 152, and an A/C adapter 160 that extendselectricity from an external socket to power the portable computer 100.The communication cradle 150 also includes one or more ports forparallel and/or serial data transfer with other computers or datanetworks. The portable computer 100 may use the communication cradle 150for the purpose of downloading and uploading software, and forsynchronizing data on the portable computer 100 with a personal computer(not shown, but may be included or used with some embodiments of theinvention). The communication cradle 150 couples to the portablecomputer 100 through a connector (see FIGS. 2-4) of the stand 152. Abutton 155 may effectuate an electrical connection between thecommunication cradle 150 and the portable computer 100 when the two areconnected.

In an embodiment, the portable computer 100 includes hardware and/orsoftware to detect whether the communication cradle 150 is activelyconnected to the portable computer 100. One advantage provided by thisembodiment is that software on the portable computer 100 may be alteredand/or reconfigured to optimize functions of the portable computer 100according to whether the accessory device is actively connected. In thisway, the portable computer 100 may launch programs that are practicalonly when external power is available. FIG. 1 shows that the portablecomputer 100 may, for example, run a program to continuously display aworld-clock on the display 114 when the communication cradle 150 isdetected. Importantly, in this example, the type of accessory deviceindicates that the power is being supplied from an external source soleaving the portable computer 100 does not drain the battery.

The portable computer 100 also accommodates alternative types ofaccessory devices, such as a modem port or a USB cradle. An embodimentof the portable computer 100 under this invention may include resourcesto detect a type of accessory, and may further alter or reconfiguresoftware to accommodate the specific accessory type without requiringuser input. This feature safeguards against the portable computer 100being prompted to execute an application for the wrong accessory device.For some accessory devices such as USB cradles, the accessory device maybe damaged if the portable computer executes an application for anothertype of accessory device such as a modem port. This invention providesthat the portable computer 100 will run the correct application for aparticular accessory type. For example, the portable computer 100 willnot execute the modem application if the accessory device is a USBdevice or cradle. In this manner, the portable computer 100 mayimplement software for a particular accessory type with minimal userattention, while precluding the possibility of running a program for thewrong accessory device.

Detecting an Accessory Device

FIG. 2 is an illustrative block diagram showing additional details of anembodiment of the portable computer 100 connected to communicate with anexemplary accessory device. In the embodiment shown by FIG. 2, theaccessory device is the plug-in communication cradle 150 having aparallel communication port for coupling the portable computer 100 to anexternal processor. The communication cradle includes an integrated A/Cadapter for operating the portable computer 100 independent of aninternal battery source.

With further reference to the embodiment of FIG. 2, the portablecomputer 100 includes a processor 210, a memory, and a battery source230. Preferably, the processor 210 is a Motorola EZ Dragonball 328™processor, and the memory 215 is a separate component that providesRandom Access Memory (RAM). The battery source 230 internally powers theprocessor 210 and memory 215, as well as other electrical componentswithin the portable computer 100. The battery source 230 may be standarddisposable batteries, or rechargeable such as Lithium-ion batteries. Theportable computer 100 also includes a communication port 232 having apin connector for coupling to a mating pin connector accessible in anoutput port 272 of the communication cradle 150.

The processor 210 extends a signal line 205 to a pin element of the pinconnector of the output port 272. The portable computer 100 andcommunication cradle 150 may electrically connect using only some of thepin elements of the respective pin connectors. For example, thecommunication port 232 may include a ten pin male connector, where ninepins are designated for functions such as parallel data transfer,parity, and “hot sync” functions for coupling the portable computer 100with another computer. One remaining pin is available for couplingwithout affecting the remaining pins. The example shown in FIG. 2couples the available pin to the signal line 205. In one configuration,the signal line 205 and the available pin are initially pulled highusing a pull-up resistor. When the pin connector is mated toelectrically connect with the communication cradle 150, the pin andsignal line 205 are pulled low. The change in voltage on the signal line205 signals the processor 210 that an electrical connection between thecommunication cradle 150 and portable computer 100 is established. Theprocessor 210 may then execute a program based on the accessory devicebeing actively connected to the portable computer 100.

The programs executed by the processor 210 include certain softwareapplications that preserve battery resources. The portable computer 100may have a time-out feature designed to significantly reduce the powerconsumption of the device when the portable computer is inactive or notin use. In general, the time-out feature operates by switching theportable computer 100 from a state of high power consumption to a stateof low power consumption when the portable computer detects inactivityfor a predetermined duration of time.

Portable computers typically use some power at all times for the purposeof maintaining a clock, memory etc. Therefore, the portable computer 100may include multiple states of power consumption, rather than just the“on” and “off” mode. The states of the portable computer may include the“doze-mode” in which the display 114 is powered, but some resourceswithin the portable computer 100 have stopped. The states of theportable computer 100 may also typically include a “sleep-mode”, wherethe portable computer 100 is consuming significantly less power, butperforming a few limited functions such as maintaining the clock.

The time-out feature provides that the portable computer 100 enters astate of low power consumption such as the sleep-mode if the processor210 is substantially inactive after a predetermined time-period. Forexample, the known art provides that the portable computer 100 maytime-out into the sleep-mode when user activity ceases for more than twominutes. In devices such as PalmPilot™ organizers, the time-out featuremay be programmed by the user to vary between one and three minutes.

In an embodiment of the invention, a change in voltage on the signalline 205 may signal the processor 210 to alter a portion of a programand execute code for suspending or prolonging the occurrence of thetime-out feature. In one embodiment of this invention, the portablecomputer 100 has a switch to alternatively allow the user to selectivelyoverride the normal behavior of the time-out function when thecommunication cradle 150 is active. The portable computer 100 may alsodetect the change in the voltage on the signal line 205 for the purposeof informing the user that the communication cradle 150 is activelyconnected.

One advantage of suspending the time-out feature includes allowing theuser to continually access the portable computer 100 without having toswitch it on.

Disabling the time-out feature, or otherwise modifying the time-outfeature, also allows the portable computer 100 to be optimized forcertain software applications that either require minimal user interfaceor require proportionately greater amounts of power. Examples of suchapplications include energy intensive software programs that havefunctions outside traditional function such as of maintaining a calendarand phone numbers. For example, the portable computer 100 may includesoftware for displaying digital photographs. Suspending the time-outfeature enables the portable computer 100 to be used as a picture frame.Other examples of software applications that may be launched when theportable computer 100 has access to plug-in power include games, a worldclock display, or a computer desktop companion. Suspending the time-outfeature may also be used to execute applications that continuouslycommunicate with and/or display information from a data network. Suchapplications may be used to display information such as a stock marketticker.

In another embodiment of the invention, the change in voltage on thesignal line 205 resulting from coupling the communication cradle 150 maysignal the processor 210 to alter a portion of a program for suspendingor prolonging a time-out for a backlight display. Previous portablecomputers provide for the software control program to turn the backlightoff to conserve battery power. In this embodiment, the backlight may becontinuously powered when the processor 210 detects the communicationcradle 150. Alternatively, the backlight can be selectively turned on oroff independent of the display screen when the processor 210 determinesthat the communication cradle 150 is electrically connected to theportable computer 100.

By detecting whether an accessory device is actively connected, theprocessor 210 may also alter or reconfigure software to provide analternative software arrangement for routine uses of the portablecomputer 100. For example, the processor 210 may be programmed tointerpret the presence of an actively connected communication cradle 150as representing a “home” position. In response to detecting an activelyconnected communication cradle 150, the processor 210 may alter orreconfigure the software to more readily accommodate a home defaultposition. The software may, for example, be altered to redisplay adatabase in a new order. Accordingly, the portable computer 100 may listpersonal phone numbers as a default file in a menu, and list homefinances as a default in a spreadsheet application, and display only“to-do” tasks such as household chores. Then, when the portable computer100 and the accessory device are not electrically connected theprocessor may run software for a professional setting, including listingprofessional numbers and calendar items.

Detecting a Type of an Accessory Connected to the Portable Computer

FIG. 3 is a block diagram schematic of another embodiment of thisinvention where a portable computer is equipped to distinguish differenttypes of accessories. In this embodiment, the portable computer 100includes the processor 210, analog-digital (A/D) converter 320, and thebattery source 230. The portable computer 100 also includes a memory 215connected to the processor 210. The processor 210 is preferably aMotorola EZ Dragonball 328™ that is connected to the A/D converter 320via an 8-bit connection 312. The A/D converter 320 preferably includesfour channels. A first and second channel 322 and 324 of the A/Dconverter 320 are dedicated for display operations. A third channel 326couples to the battery source 230. In this embodiment, a fourth channelof the A/D converter 320 is used as a signal line 328 to extend to acommunication port 232 of the portable computer 100. The A/D converter320 couples to the battery source 230 via the third channel 326 toreceive a reference voltage for a comparator (not shown) incorporatedwithin the A/D converter 320. The communication port 232 may include amale pin connector for coupling and electrically connecting with anaccessory device.

In the embodiment of FIG. 3, an accessory device 350 provides a constantvoltage on an output node 365. The accessory device may be one ofseveral devices, including the communication cradle (shown by numeral150 in FIG. 1), modem devices and USB cradles. The output node 365 ofthe accessory device 350 is accessed through an output port 272 to thepin connector for the communication port 232. Previous systems providefor coupling the portable computer 100 and accessory device 350 usingonly some of the pin elements of the 10-pin connector. As mentioned inthe embodiment of FIG. 2, the communication port 232 provides a male pinconnector with nine pins designated for functions such as parallel datatransfer and parity, and one pin being left available for alternativeuses. Each type of accessory device may be assumed to have a uniqueconstant voltage on a corresponding output node that is accessible bythe portable computer 100 through the communication port 232. Therefore,one improvement provided by some embodiments of this invention includescoupling the available pin between the A/D converter 320 and the outputnode of an accessory device for the purpose of detecting anddistinguishing accessory devices from each other.

In an embodiment, the A/D converter 320 receives a reference voltagefrom the battery source 230, and an input signal from the signal line328 extending through the available pin of the communication port 232.The A/D converter 320 may then (1) determine whether an accessory deviceis actively connected to the portable computer 100 via the communicationport 232, as described in FIG. 2; and/or (2) determine the type ofaccessory device being electrically connected to it.

The portable computer 100 and the accessory device 350 may be connectedso that the signal line 328 electrically contacts a mating pin in theoutput port 272 of the accessory device 350. When the accessory device350 is powered, a voltage is provided on the output node 365 and to thesignal line 328. The voltage on the signal line 328 is detected by theA/D converter 320. A comparator within the A/D converter 320 comparesthe voltage on the signal line 328 with the reference voltage suppliedfrom the battery source 230 via the third channel 326. The A/D converter320 can signal the memory 215 for the purpose of matching the voltage onthe signal line 328 with a type of accessory. The voltages on the outputnode 365 of each type of accessory device may be predetermined andstored in a look-up table of the memory 215. Therefore, the look up maylist accessory types according to the voltage on a corresponding outputnode of each accessory type. Once the memory 215 is signaled, theprocessor 210 may execute software to match the voltage on the signalline 328 with a type of accessory using the look-up table. For example,a modem port may provide a voltage on an output node that isdistinguishable from a voltage on an output node of a communicationcradle, such as the one shown in FIG. 1. Similarly, a USB cradle ordevice provides an output node having a distinguishable voltage from themodem port or cradle.

Distinguishing between accessory devices in this manner enables theportable computer 100 to select or alter programming to accommodate onedevice over another in a quick and cost efficient manner. For example,the portable computer 100 can immediately detect the presence of the USBcradle and alter software to accommodate the USB cradle. This alterationto the software can be done when the portable computer is in adoze-mode, so that the user has quicker access to functions availablefrom coupling the USB device. In another example, the portable computer100 may be used to preclude inadvertent detection of a modem port,because transmitting or altering programs for a modem port that is notexistent can be damaging to the system.

FIG. 4A is a block diagram schematic of another embodiment in which aportable computer 100 is equipped to determine the type of accessoryactively connected to it. In this embodiment, the portable computer 100includes a processor 210, a memory 215, an analog-digital (A/D)converter 320, and a battery source 230. As with the previousembodiment, the processor 210 is preferably a Motorola EZ Dragonball™328 that is connected to the A/D converter 320 using an 8-bit connection312. The memory 215 may store a look-up table similar to the embodimentof FIG. 3. The A/D converter 320 preferably includes four channels. Afirst and second channel 322 and 324 of the A/D converter 320 arededicated for display operations. A third channel 326 couples to thebattery source 230. A fourth channel of the A/D converter 320 is used asa signal line 328 to extend to a communication port 232 of the portablecomputer 100. The A/D converter 320 couples to the battery source 230via the third channel 326 to receive a reference voltage for acomparator (not shown) incorporated within the A/D converter 320. Thecommunication port 232 also a male pin connector for coupling andelectrically connecting with the accessory device 350.

The accessory device 350 includes a voltage divider 460, and an outputport 272 for mating with the portable computer 100. As with previousembodiments, the accessory device 350 may include one of many devices,including a communication cradle 150, modem device, or USB cradle. Theoutput port 272 includes a mating pin connector for the communicationport 232. The voltage divider 460 includes an input node 462, a firstresistor series 464, and a second resistor series 466. One end of thesecond resistor 466 series is tied to ground 468. An output node 465 isextended between the first resistor series 464 and the second resistorseries 466. The output node 465 extends a voltage to a corresponding pinslot on the output port 272. In this embodiment, a voltage of the inputnode 462 is tied to the battery source 230 of the portable computer 100via a line 429.

The embodiment of FIG. 4A provides that the battery source 230 to feedthe reference voltage to both the A/D converter 320 and to the input ofthe voltage divider 460. In this way, the voltage on the output node 465may be adjusted to account for fluctuations to the reference voltagesupplied to the A/D converter 320. This enables the A/D converter 320 tomore accurately detect the voltage on the output node 465. Additionalprecision in determining the voltage in turn allows for a larger andmore accurate match between detected voltages and corresponding devicetypes. In this manner, the embodiment of FIG. 4A may be employed todistinguish among different accessory types similar to previousembodiments, but more accurately matches the voltage on the signal line328 with the matching accessory type. Employing an 8-bit A/D converter320 in this manner allows for up to 256 different accessory types to bematched to a distinct voltage on the signal line 328.

FIG. 4B is an embodiment similar to FIG. 4A except that the voltagedivider 460 is now distributed between the portable computer 100 and theaccessory device 350. In this embodiment, the voltage of the output node465 may be determined based on a resistor series contained within theaccessory device 350 that is tied to ground. The input node 462 and thefirst resistor series 464 couple to the battery source 230 within theportable computer 100. A voltage line 414 passes from the first resistorseries 464 through the communications port 232, the output port 272 andinto the accessory device 350. The voltage line 414 couples with asecond resistor series 464 connected to ground 468 that forms thevoltage divider 460. The voltage line 414 may be passed through one ofthe pin elements of the pin connectors used to couple the portablecomputer 100 and accessory device 350, such as the second pin shown inFIG. 2. FIG. 4B represents an alternative configuration in which theaccessory device supplies a voltage from the battery source to produce adistinguishable voltage on the output node 465. Since the input voltageprovided to the accessory device 350 is the same as the referencevoltage to the A/D converter 320, the A/D converter is able to betterdistinguish between voltages on the output node 465.

Algorithm for Detecting an Accessory Device

FIG. 5 is a flowchart showing the steps by which a portable computerdevice such as the one shown in FIG. 2 operates depending on whether anaccessory device such as the communication cradle 150 is activelyconnected to it. In an embodiment of this invention, the algorithmdescribed herein may be implemented with the portable computer 100 andthe communication cradle 150 supplying the portable computer 100. Thecommunication cradle 150 described with this embodiment is intended toonly be an exemplary accessory device that provides communicationabilities and external power to the portable computer 100.

In step 510, the portable computer 100 receives a signal from thecommunication cradle 150. This step may be accomplished by signaling tothe processor 210 the voltage on the signal line 205. In step 515, theprocessor 210 determines whether the communication cradle 150 isactively connected to the portable computer 100. This is preferablydetermined by a voltage on the signal line 205 being either high or low.In a corresponding embodiment, the signal line 205 floats high and ispulled low when actively connected. Under this configuration, theprocessor 210 determines that the communication cradle 150 is activelyconnected when the voltage on the signal line 205 is low.

If an accessory is detected, the portable computer 100 in step 520alters programming of the software to disable the time-out. Toaccomplish this step, the processor 210 may execute programming tosuspend or delay the time-out feature from turning the portable computerto a state of reduced power consumption. If an accessory is notdetected, step 530 shows that the processor 210 will resume normaloperations, in which case the portable computer 100 turns off after apre-programmed duration in which the time-out feature becomes effective.

Algorithm for Detecting a Type of an Accessory Device

FIG. 6 is a flowchart showing the steps by which a portable computerdevice such as the one shown in FIGS. 3-4 determines the type ofaccessory device that is actively connected to it. For descriptivepurposes, components used to describe the flowchart may be referencedwith respect to the assembly shown by FIG. 4, so that the algorithm maybe implemented with the portable computer 100 and any one of theaccessory devices disclosed herein, including the communication cradle150, modem device, and USB cradle.

In step 610, the signal from the accessory device is measured. This maybe accomplished using the A/D converter 320 to measure the voltage valueof the signal on the signal line 328.

In step 620, the algorithm determines the type of accessory by matchingthe signal value to the accessory type, by for example, using a look-uptable. The A/D converter 320 may determine the voltage in counts, andthe processor 210 then compares the counts to values stored in thelook-up table. The look-up table is preferably stored in the memory 215.In step 620, the processor 210 performs steps of a program according tothe type of accessory being connected to the portable computer 100. Forexample, the comparator will run a modem application if a modem isdetected by the signal line 328, or disable the time-out feature if thecommunicator cradle 150 is detected.

The portable. computer 100 may detect any one of n accessory types,where n represents the number of voltage counts that the A/D convertercan detect. With an 8 bit connection between the A/D converter 320 andthe processor 210, the A/D converter may be used to detect up to 256different types of accessories. Other “types” of accessories that may berecognized by the portable computer 100 include “no accessory”, and an“unknown accessory”. A possible step 632 shows, for example, that if thevoltage count is 0, then no accessory is detected. The portable computerthen resumes normal operations in step 642, which assumes batteryoperation with no accessory device.

The processor 210 may alternatively execute step 634, which shows an“unknown” type of accessory for when the voltage determined by the A/Ddoes not match to a corresponding type of accessory in the look-uptable. Subsequently, step 644 shows that an error message is thendisplayed to notify the user that the accessory device does not matchthe portable computer 100.

The processor may determine, in step 636, that a first type of accessorydevice is actively connected to the portable computer 100. As shown bystep 646, the processor 210 in step 646 alters the software byperforming steps that accommodate the particular type of accessory. Inpossible steps 638 and 648, the processor 210 detects from one of othertypes of accessories, and program the portable computer to accommodatethe particular accessory.

This invention is intended to encompass an embodiment combining thesteps shown in FIGS. 5 and 6. Therefore, under an embodiment of thisinvention, a portable computer may determine first whether an accessorydevice is connected to it, and next determine the type of accessorydevice that is connected.

Alternative Embodiments

Several variations and additional features may be incorporated inembodiments of this invention.

For setting software depending on whether an accessory device such as acommunication cradle is actively connected to the portable computer, aswitch may be provided that switches the voltage on the signal line fromhigh to low or vice versa. The switch may be used to set a softwarearrangement for routine uses of the portable computer. In an embodiment,the switch may be used to distinguish between identical communicationcradles, where one of the communication cradles is used for a firstoperational environment, and another of the communication cradles isused for another operational environment. Therefore, a user may assignone of the communication cradles to represent the “home” position, wheredata is arranged to prioritize personal information over professionalinformation. Similarly, the switch may distinguish the othercommunication cradle to represent a “work” position, where the dataarrangement prioritizes professional information.

In an embodiment of the invention, software on the portable computer 100may be configured or set to accommodate a particular type of accessorydevice connected to the portable computer 100 even when the portablecomputer is a sleep-mode. For example, a modem device may be connectedto the portable computer 100 in a sleep-mode. The portable computer 100detects the voltage on the signal line and sets a data value based onthe modem device. When the portable computer 100 is subsequentlyswitched to an “on” or “doze” mode, the portable computer immediatelymakes the modem device available. Minimizing access time in this mannermay provide significant advantages to portable computer s incorporatingthis embodiment of the invention, in that use of the portable computeris often intermittent and for relatively short durations.

Conclusion

The foregoing description of various embodiments of the invention havebeen presented for purposes of illustration and description. It is notintended to limit the invention to the precise forms disclosed. Manymodifications and equivalent arrangements will be apparent.

What is claimed is:
 1. A method for operating a portable computingdevice, the method comprising: coupling a signal line accessible throughan outlet of the portable computing device to a communication device;detecting a signal on the signal line to determine whether thecommunication device is actively connected to a portable computingdevice; and suspending execution of at least a portion of a program, theportion of the program including instructions for reducing powerconsumption of the portable computing device; wherein suspendingexecution of at least a portion of a program for reducing powerconsumption of the portable computing device includes determining aprogrammable backlight of a display to be operational while thecommunication device is coupled.
 2. The method of claim 1, whereincoupling a signal line includes extending the signal line to a pinelement of a pin connector forming the outlet.
 3. The method of claim 1,wherein detecting the signal includes measuring a voltage level of thesignal.
 4. The method of claim 1, wherein detecting a signal from thecommunication device includes coupling the portable computing device tothe communication device using a pin connector, and wherein one pin inthe pin connector extends into the signal line.
 5. A method foroperating a portable computing device, the method comprising: coupling asignal line accessible through an outlet of the portable computingdevice to a communication device; detecting a signal on the signal lineto determine whether the communication device is actively connected to aportable computing device; and suspending execution of at least aportion of a program, the portion of the program including instructionsfor reducing power consumption of the portable computing device; whereinsuspending execution of at least a portion of a program for reducingpower consumption of the portable computing device includes programminga backlight of a display to be selectively operational while thecommunication device is coupled.
 6. The method of claim 5, whereinsuspending execution of at least a portion of a program for reducingpower consumption of the portable computing device includes programmingthe display to be operational when the backlight of the display isselected to be operational.
 7. The method of claim 5, includingexecuting a program upon detecting the signal on the signal line toreorganize an output arrangement of a database.
 8. A detachableassembly, comprising: a communication device; and a portable computingdevice adapted to couple to the communication device, the portablecomputing device including: a signal line that is adapted to couple toan output node of the communication device; and a processor coupled todetect a signal on the signal line to determine whether thecommunication device is actively connected to the portable computingdevice; wherein the processor is programmed to suspend execution of atleast a portion of a program upon detecting the communication device,the portion of the program including instructions for reducing powerconsumption of the portable computing device, the portion of the programfurther including instructions for providing a backlight of a display tobe operational while the communication device is coupled.
 9. Thedetachable assembly of claim 8, wherein the signal is a voltage levelprovided by the output node of the communication device.
 10. Thedetachable assembly of claim 8, wherein the portable computing devicecouples to the communication device using a pin connector, and whereinone pin in the pin connector extends into the signal line.
 11. Adetachable assembly, comprising: a communication device; and a portablecomputing device adapted to couple to the communication device, theportable computing device including: a signal line that is adapted tocouple to an output node of the communication device; and a processorcoupled to detect a signal on the signal line to determine whether thecommunication device is actively connected to the portable computingdevice; wherein the processor is programmed to suspend execution of atleast a portion of a program upon detecting the communication device,the portion of the program including instructions for reducing powerconsumption of the portable computing device, the portion of the programfurther includes instructions for providing a backlight of a display tobe selectively operational while the communication device is coupled.12. The detachable assembly of claim 11, wherein the portion of theprogram provides for the display to be operational when the backlight ofthe display is selected to be operational.
 13. A detachable assembly,comprising: a communication device; and a portable computing deviceadapted to couple to the communication device, the portable computingdevice including: a signal line that is adapted to couple to an outputnode of the communication device; and a processor coupled to detect asignal on the signal line to determine whether the communication deviceis actively connected to the portable computing device; wherein theprocessor is programmed to suspend execution of at least a portion of aprogram upon detecting the communication device, the portion of theprogram including instructions for reducing power consumption of theportable computing device, wherein the portion of the program furtherprovides instructions for reorganizing an output arrangement of adatabase.